#define _CRT_SECURE_NO_WARNINGS 1

#include "Stack.h"

void STInit(ST* ps)
{
	assert(ps);

	ps->capacity = 4;
	ps->top = 0;

	STDataType* tmp = (STDataType*)malloc(ps->capacity * sizeof(STDataType));
	if (tmp == NULL)
	{
		perror("malloc fail");
		return;
	}
	ps->a = tmp;
}

void STDestroy(ST* ps)
{
	assert(ps);

	free(ps->a);
	ps->a = NULL;
	ps->capacity = ps->top = 0;
	ps = NULL;
}

void STPush(ST* ps, STDataType x)
{
	assert(ps);

	if (ps->capacity == ps->top)
	{
		STDataType* tmp = (STDataType*)realloc(ps->a,2 * ps->capacity * sizeof(STDataType));
		if (tmp == NULL)
		{
			perror("realloc fail");
			return;
		}
		ps->a = tmp;
		ps->capacity *= 2;
	}

	ps->a[ps->top++] = x;
}

int STSize(ST* ps)
{
	assert(ps);

	return ps->top;
}

bool STEmpty(ST* ps)
{
	assert(ps);

	return (ps->top == 0);
}

void STPop(ST* ps)
{
	assert(ps);
	assert(!STEmpty(ps));

	--ps->top;
}

STDataType STTop(ST* ps)
{
	assert(ps);
	assert(!STEmpty(ps));

	return (ps->a[ps->top - 1]);
}